Pulse width modulation (PWM) systems are often employed to generate analog signals from digital data. PWM signals are used to drive an H-bridge or similar device to be used to drive a headphone amplifier, a Class A, B, AB amplifier, or other circuitry. In some instances, PWM signals are used to drive auxiliary amplifier circuitry to achieve high-power and high-efficiency amplification.
One problem with conventional DACs is that linearity can be difficult to achieve. In particular, circuit component mismatches can introduce dynamic non-linearities in the switching output signal. To achieve a desired signal-to-noise ratio (SNR) and/or signal-to-noise-and-distortion ratio (SNDR) (i.e., linearity), a DAC should be immune to such mismatches.